The Metro board's longest serving member, Arlington County Board Vice Chairman Chris Zimmerman (D), announced unexpectedly Thursday that he is resigning from the Metro position at this year's end.

In addition, the board's second longest serving member, D.C. Council member Jim Graham (D-Ward 1), is virtually certain to be ousted from his seat by the incoming D.C. Council chairman, Kwame R. Brown (D).

Graham is probably the Metro board's best-known member. Wearing his trademark bow tie and oversize eyeglasses, he was constantly in the news in 2009 when he served as Metro board chairman at the time of the Red Line crash that killed nine and jolted the region out of its complacency about Metro's problems.

The twin departures represent a significant and welcome shake-up in Metro's leadership. Although both men have been hardworking and knowledgeable advocates for the system for more than a decade, their time has passed.

Metro needs fresh oversight, especially as the board prepares to pick a new, permanent general manager in early 2011. It needs directors eager to embrace new approaches necessary to fix problems that have been building for years, especially to improve safety and maintenance.

Graham and Zimmerman are not the right fit for those tasks. They were two of the board's most engaged and influential members during the years when Metro failed to build a safety culture and allowed maintenance to erode.

They both believe that Metro's only real problem is lack of money, when in fact ineffective management and governance share much of the blame. Studies by a series of outside experts, ranging from federal safety monitors to private business consultants, have repeatedly concluded that Metro has been poorly run in numerous ways.

Of course, there's no guarantee that the two replacements on the board, which has eight voting members, will do any better.

Filling Zimmerman's seat starting in January will be fellow Arlington County Board member Mary H. Hynes (D).

In the District, council Chairman-elect Brown is likely to appoint D.C. Council member Tommy Wells (D-Ward 6) to replace Graham, according to people familiar with Brown's thinking. They spoke on condition of anonymity because an official announcement isn't expected until Tuesday.

Graham, who was scheduled to talk to Brown on Monday, said Saturday that he still hoped to remain on the board. But he was philosophical about the prospect of departing after nearly 12 years, saying: "I think there's an overwhelming desire for change right now on the Metro board. Obviously it's affected Zimmerman, it's affected others."